Analysis - After nine years in opposition New Zealand First is poised once again to be in government.
It now has to decide whether to support a National-led fourth-term government or a Labour government, supported by the Green Party.
New Zealand First's last go in government was from 2005 to 2008 under Helen Clark's administration.
However, that ended badly as the party's own political problems forced its leader Winston Peters to stand down as foreign minister. In 1998, its coalition with National imploded over a dispute over asset sales.
Based on the results from election night New Zealand First has nine MPs in the new Parliament. They and their party board will have to decide who to support.
So who are they?
There is little need to introduce Mr Peters. He founded New Zealand First in 1993 and has been its leader ever since.
He was originally a National Party MP and Minister of Māori Affairs from 1990 until the then prime minister, Jim Bolger, sacked him in October, 1991.
Despite bad blood with his old party, New Zealand First entered a coalition with National after the 1996 election but it ended badly with the coalition collapsing in 1998.
Mr Peters's party also disintegrated but survived to scrape back in at the 1999 election.
Then in 2005, Mr Peters led his party back into government after reaching a deal with Labour. That too ended badly but not because of any disagreement with Labour.
Mr Peters talks fondly of his time in that government, believing that Labour's leader Helen Clark and deputy leader Michael Cullen treated him with respect.
At the 2008 election New Zealand First fell short of the five percent threshold needed to win seats in Parliament. Many commentators wrote the party off, but Mr Peters led it back to Beehive three years later.
Now in what could possibly be his last term - Mr Peters is 72 - he has the chance again to prove his critics wrong.
Ron Mark is a former soldier who got his first taste of politics standing for the Labour Party in Selwyn. He later joined New Zealand First and became a list MP after the 1996 election. He lost his seat in 2008 when the party failed to make the 5 percent threshold.
In 2010 he was elected mayor of Carterton but stood down in 2014 to return to Parliament.
A year later he replaced Tracey Martin as the party's deputy leader.
Tracey Martin has a long history with New Zealand First, being involved with the party since its formation in 1993. She has been a member of the party's board of directors since 2008 and was elected to Parliament in 2011 and appointed deputy leader.
She was replaced as deputy by Ron Mark in 2015.
One senior Labour MP describes Mrs Martin as a Labour MP in all but name and she appears to have a good relationship with women MPs from the Green Party.
Fletcher Tabuteau was an economics lecturer and head of the business school at the Waiariki Institute of Technology, and before that a secondary school teacher in Rotorua.
He stood for New Zealand First in 2002, 2005 and 2011 before being elected to Parliament as a list MP in 2014. He too has been a member of the party since its formation.
Darroch Ball is a former army officer and teacher and is now based in Palmerston North. He spent time in the Army working with the Limited Service Volunteer programme and then qualified as a teacher in 2013.
He began teaching biology and science at Waiopehu College in Levin.
Mr Ball became a member of New Zealand First's board of directors in 2012 and was elected to Parliament in 2014.
Clayton Mitchell is a Bay of Plenty businessman who was first elected to Parliament in 2014.
He is the party's associate whip and spokesman for conservation, internal affairs, labour and industrial relations and sport and recreation.
Shane Jones is a new MP but, like Winston Peters, needs little introduction.
He left his position as Ambassador for Pacific Economic Development to stand for New Zealand First in Whangarei. He lost but comes in as a list MP.
Formerly he had been an MP and minister in the previous Labour Government.
He faced embarrassment in 2010 when he admitted he had used his ministerial credit card to hire pornographic movies at hotels while on ministerial business. Despite that he still contested the Labour leadership in 2013 but lost to David Cunliffe.
Mr Jones left Parliament in May 2014 to take up his ambassador's role.
Jenny Marcroft is a former broadcaster and teacher. She contested the Tamaki seat for New Zealand First. When she was selected as a candidate, the party's leader Mr Peters described her as a most talented communicator.
"With over 30 years of frontline experience in the broadcasting world she brings a wealth of experience and knowledge to our team," he said.
Mark Patterson is a sheep farmer from Southland who previously sought unsuccessfully to replace Bill English as National's candidate in Clutha-Southland. He then joined New Zealand First in 2015.
In an interview with Stuff earlier this year Mr Patterson said he did not believe National was serving the best interests of rural people.
"We desperately need that alternative political voice, apart from the National Party, because in my view we've really been taken for granted."